(1) Field of Invention
This invention relates to humidifiers of the type for use in providing humidified gases to a patient in a hospital in need of such humidified gases. The invention has been devised particularly though not solely for providing methods of and/or apparatus for providing an indication as to when the humidity of a humidified gas or gases supplied by a humidifier of the type described is unacceptably low in many applications, and for providing methods of and/or apparatus for removably securing a humidifying chamber to humidifying apparatus.
(2) Prior Art
Humidifiers for supplying humidified gas to a patient, eg. a hospitalised patient are known. A humidifier of this type which includes a humidifying chamber is described in the specification of our U.S. Pat. No. 4,203,027. One of the problems associated with humidifiers of this type is that humidified gases are supplied some distance through gas conduits from the humidifying chamber to the patient, which causes the humidified gases to cool before reaching the patient Such cooling reduces the humidity of the gases and condensation will often form on the inner walls of the conduit. In order to help prevent such cooling, heating elements may be provided within the humidified gases conduit. However, care must be taken not to maintain the humidified gases at too high a temperature when supplied to the patient, since gases at high temperatures will cause burns or at least make the patient uncomfortable.
Humidifiers of the type which have a humidifying chamber which slides on to a base such as a heater plate of the humidifier are also disclosed in the specification of our U.S. Pat. No. 4,203,027. Although such a sliding action facilitates placing the humidifying chamber on the heater plate of a humidifier, it is also relatively easy for the humidifying chamber to be dislodged from the heater plate, preventing operation of the apparatus.